Braking Away: Upgrading the disc brakes on a 68-82 C3 Corvette

We waited until the last minute to decide which brake calipers toinstall on Project Shark Attack (PSA) and are now glad of it. Once wehad an idea what funds could be allocated to the project, it made senseto install the new Stainless Steel Brake Corporation (SSBC) Force 10Extreme four-piston aluminum calipers.

The new (and we emphasize new) forged aluminum, lightweight calipers arethe first major advancement in '65-'82 Corvette calipers since thesecars were built. The calipers are a fixed-position-type, but the sealingrings ride on the stainless steel caliper pistons instead of the caliperhousing bore. This means if there is a caliper piston seal problem downthe road, they can be replaced without messing with the housing, unlikethe originals.

The SSBC caliper pistons fit tighter in the caliper bore than theirpredecessors so the piston and seals will live longer. An interestingphenomenon occurs as the rotors move slightly from inherentwheel-bearing clearances. It pushes the caliper pistons back into theirbore just enough to eliminate drag. This was the downfall on theoriginal-design calipers, due to the pistons fitting loosely in thecaliper, the pads dragged (slightly) all the time. The other problemwith the original design was the caliper housing bore and seal wear wasaccelerated when the rotors didn't run parallel.

For our project, we were able to include the SSBC Turbo slotted rotorswith the new trick SSBC calipers. SSBC coats their rotors with anXtra-life plating to keep the rotors looking good for many miles. Eventhough the SSBC calipers aren't as particular about rotor parallelism,we checked run-out at each corner before fitting the calipers in place.After the runout check, we proceeded to do the rest of the install.

Once the brakes are bled, have someone apply pressure to the brake pedaland check for leaks. We always go around the car one more time after thebleeding sequence and tighten the bleeders and lines just to be safe.Check the brake pedal feel before leaving the driveway, then take yourCorvette out and break in the disc pads. Three moderate stops from 45mph for five repetitions will seat the pads to the rotors for maximumpedal feel. After the first three sets of stops, make sure you let thepads cool down before doing another set of two stops, until the fiverepetitions are complete. Now you should feel the real difference theSSBC brake system has made to your Corvette.

After putting 8,000-plus miles on Project Shark Attack, we woulddefinitely recommend the SSBC calipers and rotors package. They deliversure, even braking under all road conditions. Over this same timeperiod, there has been no squealing from the disc pads.

All needed hardware is included in the caliper kit: disc pads,anti-rattle clips, shims, mounting bolts, and S/S hoses. It's also aplus to lose some unsprung weight, and, of course, the aluminumcomponents are easier to handle during installation and servicing.

On a final note, the slick, stainless-steel calipers and Xtra-lifeplated rotors sure look good through those five-spoke, 16-inch Corvettewheels on PSA.

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Braking Away: Upgrading the disc brakes on a 68-82 C3 Corvette

PSA had the rotors replaced at least once before, so we didn't have todrill out the rivets to remove the rotors. Be sure there are no burrs ordings in the hub, preventing the rotor from sitting flat against thehub. Sometimes, when the rivets are pushed out for rotor removal, highspots occur around the rivet hole causing the rotor to sit at an angle.We use a small sander to knock down any obvious high spots.

We slid the rotors over the freshly packed wheel bearing hubs for therunout check. The rotor should have a maximum of .004 runout during onefull revolution of the rotor. This runout figure holds especially truewith conventional calipers. Be sure to turn the lug nuts over andtighten all five for a true runout reading.

Boy, did we have a high spot! After cleaning the hub, you can see we had.010 runout. If we find a high spot, we mark the rotor and the stud atthe highest point and record the figure. There is a good chance we willfind a problem considering the age and abuse the hubs take. The rotorsand hubs can be assembled, torqued, and then machined as an assembly toeliminate runout, but you would already be removing material from therotors surface.

First, we try changing the position of the rotor on the hub to alleviatea high spot. You have four chances to make it better. Sometimes thisprocess helps, and sometimes it makes the runout worse. We also trychanging the rotors from one side to the other if possible. With ourdirectional SSBC Turbo-slotted rotors, we didnt have that luxury. Youcant change the position of rear rotors on the hubs because of thedrilled holes for emergency brake adjustment unless you want to removethe rotors for brake adjustment.

We've been using brass shim material in .005 increments from ACEhardware for shimming. We place a shim between the rotor and hubassembly opposite the high spot. Remember, the high spot will also belower when a .005 shim is placed on the low spot. We also found thatmoving the shim on either side of the high spot sometimes is required.Be patient, this procedure can be very aggravating at times.

Now that we're happy with our final runout reading, we record the finalrunout reading on the rotor and mark where our shim is placed. Thecorresponding stud is also marked so the rotor can be reinstalled in theproper location. We're very pleased with the .002 final reading.Excessive runout can be heard when you're riding next to a wall. Therhythmic squeaking would be telling you that the rotors aren't parallel.

Once you're satisfied with the rotor runout, the calipers go on next.The SSBC calipers may require shimming to center the caliperside-to-side over the rotor. This is important for even disc-pad wear.Also, improper shimming can bind the caliper pistons. We found thatstarting the caliper mounting bolt opposite the side that requires theshims makes shim installation easier. Here, the lower mounting point ofthe driver-side front caliper needed shims. We used the K&S Brass Shimmaterial PN 250 (.005X4X10) from Ace Hardware.

The disc pads slide in place like the original calipers except that twopins hold them in position. If the shimming was done properly, the discpads should drop in place. No hammer is necessary. The rotors shouldturn freely if the shimming is correct.

The supplied antirattle clip is caught under the rear disc-pad retainingpin and then it hooks under the front pin. These antirattle clips workwell without binding the pads like some of the aftermarket clips thatwere used on the OE calipers.

All that's left to do is to install the S/S braided hoses and bleed thesystem. Now's the time to go around and check all the calipers for theproper mounting bolt torque of 65 lb-ft and proper pad clearance onemore time.

We used a line wrench to loosen and tighten the 3/8-inch line fittingwhile holding the hose with an 1116-inch wrench. If you have troubleremoving the line fitting nut, cut the old hose off and apply heat witha torch on the hose fitting. This process works well and keeps thefitting in good shape. Make sure you cut the old rubber hose so it canbreathe or it will blow off at high speed.

We found the hoses needed to be at a 45-degree angle at the caliper forproper clearance. One thing to pay close attention to is the possiblepinch-point between the steering arm and the control arm when the wheelsare turned lock to lock. Be sure to check the hose position when yourCorvette is at ride height during full lock-to-lock turns.

Now it's time to bleed the brakes. We use a pressurized reservoir topush the silicone brake fluid to each caliper. Start with the right rearcaliper, then the left rear caliper, then go to the front of the car.Bleed the front right caliper and then the left caliper. The pedalshould have two to three inches of travel in the beginning. As the discpads seat, the brake pedal should raise slightly.

The SSBC caliper looks great between the SLP five-spoke wheels. We werethinking the calipers should be red, but they look good as is, blendingwell with the wheel. We are thinking about red for the lettering,possibly to show the caliper off with a little style.

The front wheels should now be torqued properly to 95 lb-ft, promotinglong wheel and rotor life. Slamming the lugs down with an impact wrenchcan damage the hubs and rotors, causing rotor runout concerns. It wouldbe a shame to spend the time getting the rotor runout withinspecification and then hammering the wheels on.

Want your money to go along way and have your brakes stop at a shorter distance, there many solutions and one includes getting a brake system from Wilwood, Baer Brakes, Master Power, or Stainless Steel Brakes - Super Chevy Magazine » Read More